1. Field of the Invention
The present invention relates to release mechanisms, and in particular to apparatus where normally metal materials are required to achieve the desired level of performance, where the invented apparatus may be composed entirely of an elastic thermoplastic material.
2. Related Art
Release mechanism apparatus in firing pins are designed to safely deliver the fire energy to the primer in an energetic device, such as a shell or a mine. The release mechanism apparatus must not fire or release under no fire conditions and must reliably work in all environmental conditions, and in the case of military devices, the environmental conditions may be very extreme.
Release mechanism apparatus, and in particular traditional firing pin, have been made of various metals, most notably aluminum and stainless steel. Some examples include shear, sear or three ball release systems. All three systems have trouble with friction in the axial direction because metal to metal contact occurs. To reduce the friction, high surface finishes or post manufacturing lubrication is required such as dry film lube. Extra material finishing and complexity greatly increases cost of manufacturing as well as inspection and rework. These features are critical to the successful functioning of the end item. Friction causes gouging, and may result in release failure.
The shear mechanisms use a shear pin that must be broken upon the specified load. While simple in design, the shear pin is strongly affected by the variance in the strength of materials of the pin and its geometry. The shear pin may also bind or press against an inner bore of the device creating energy loss in the firing pin action.